Carcass dressing percentage and cooler shrink

It is important for livestock producers to understand the concept of dressing percentage and cooler shrink because it can equate to profitability. Large packers often pay on dressing percentage or based off of equations that include dressing percentage. Additionally, dressing percent is an indication of how much meat a carcass will yield. Cooler shrink is important to understand when selling meat by halves and quarters to customers. It is important to ask your meat processor if they are weighing the carcasses hot or cold and adjust the price of the meat accordingly. It is not necessary to calculate a dressing percentage (often live animal weight is unknown) or cooler shrink (often either hot or cold carcass weight is unknown) when selling livestock directly to the consumer. It is important to understand the concepts of each and utilize the information when setting prices and calculating profitability for any operation selling meat animals.

Dressing percentage is based on the relationship between the dressed carcass weight and the live animal weight after things like the hide and internal organs have been removed. Dressing percentage can be calculated by taking (weight of the carcass / weight of live animal) * 100. This can be determined on a hot carcass weight or a cold carcass weight. In general, animals that are heavier muscled have a higher dressing percent than animals that are lighter muscled (see ranges, Table 1). Additionally, as the fat thickness on the outside of a carcass increases, the dressing percent also increases. Other factors that can negatively influence dressing percent are mud or manure on the hide, gut fill, amount of bone, unshorn wool, horns, abscesses, or bruises.

Cooler shrink is the amount of water lost from a carcass in the first 24 to 48 hours after harvest. This can be calculated if both the hot and cold carcass weights are known by taking (1 – (cold carcass weight / hot carcass weight)) * 100. The majority of muscle or meat is made up of water, ranging from 70 to 75% of the composition. Thus, significant amounts of this water can evaporate resulting in weight loss. Conditions in the cooler and the external fat thickness on a carcass directly impact cooler shrink. Carcasses with average or excessive amounts of fat will have less cooler shrink than trimmer carcasses.

Processors want to minimize cooler shrink and maximize cooling rate. Thus, large packing plants often use spray chilling, intermittently spraying the carcass with cold water during the first 8 hours of carcass chilling, to increase the rate of cooling and decrease the amount of shrink. Additional factors that packers monitor closely are air movement, relative humidity and carcass spacing. In large meat packing facilities, cooler shrink is often less than 1 percent. In operations where spray chilling is not used and air movement is really good, 3 to 5 percent cooler shrink could be expected. Producers that collect payment based on cold carcass weight should consider pricing 3 percent higher, or by the amount of cooler shrink experienced, to offset the difference compared to hot carcass weight. Some species, such as goats, can see up to 10 percent cooler shrink. The process is monitored so that cold shortening is avoided. Cold shortening, which can result in toughening of meat, is when meat is chilled too rapidly before rigor mortis is established and muscle structure is shortened. Cold shortening should be avoided when chilling beef and lamb carcasses

Table 1. Average and range of dressing percentage for various meat animals.